Endocardial fibroelastosis and hypoplasia of the left ventricle in neonates without significant aortic stenosis.

Endocardial fibroelastosis in neonates with hypoplasia of the left ventricle is usually associated with severe aortic stenosis or atresia. In this study three hearts were examined, in which severe hypoplasia of the left ventricular cavity with myocardial hypertrophy and endocardial fibroelastosis were associated with small but non-stenotic subaortic outflow tracts and aortic valves. These features were contrasted with those of neonatal left heart hypoplasia in aortic stenosis and atresia. The index cases were examples of the very rare contracted form of endocardial fibroelastosis.